The present invention concerns automotive shifters, and in particular concerns a shifter for manual transmissions adapted for improved shifting in a gear engaging direction.
Manual transmissions (i.e. manually shifted transmissions) for automobiles include shift sticks that are typically shifted in an "H" type pattern or similar patterns about orthogonal axes of rotation. In such patterns, the line segment at the center of the H represents neutral and typically extends side-to-side of the vehicle, while the remaining line segments extend forwardly and rearwardly of the vehicle and represent gear engaging shift directions. It is desirable to provide significant/mechanical advantage to the shift stick in the gear engaging shift direction to reduce transmission induced shift loads on the operator. This is typically done by shortening the lower portion of the shift stick below the axis of rotation and lengthening the upper portion of the shift stick above the axis of rotation, thus providing mechanical advantage to the operator when shifting. However, this results in a wide swing in the handle at the upper end of the shift stick, which is unacceptable, particularly in the side-to-side direction.
For example, the shifter of U.S. Pat. No. 07/992,243 and entitled "Flat Spring Biased Shifter" exhibits this problem in the event that a greater than normal shifting force is required to shift the transmission. In such a shifter the orthogonal axes of rotation defined by the ball-and-socket pivot arrangement of the shifter intersect. This causes an unresolvable problem since if the ball-and-socket pivot is positioned lower on the shift stick (i.e. the ratio of the upper-to-lower length of the shift stick is increased) for more leverage when shifting forwardly/rearwardly into gear, the shift stick upper end travels unacceptably far during side-to-side movement. Contrastingly, if the ball-and-socket pivot is positioned higher on the shift stick (i.e. the ratio of the upper-to-lower length of the shift stick is reduced), the shift stick lacks the desired level of mechanical advantage for gear engaging shift movement. Further, it is noted that there are spacial constraints on how close the ball-and-socket can be positioned to the transmission while still meeting other functional requirements of the shifters.
Thus, a shifter solving the aforementioned problems is desired.